Commutator for dynamo-electric machines



(No Model.)

'E. E. KNOWL S.

COMMUTATOR POE DY-NAMO ELECTRIC MACHINES. No. 396,942. Patented Jan. 29, 1889 WITNESSES: INV ETOE, Mam

ATTORNEY N. Pmzns, Fhnlo-Ldhogmpher, wuhin tm D. C.

UNITED STATES PATENT OrEicE.

EDXVARD R. KNOYLES, OF BROOKLYN, ASSIGNOR TO THE Ml'Tl'AL ELEC- TRIC MANUFAUFURIXG COMPANY, OF XE\\' YORK.

COMMUTATOR FOR DYNAMO ELECTRlC MACHINES.

SPECIFICATION forming part of Letters Patent No. 396,942, dated January 29, 1889. Application filed August 5, 1885. Renewed December 21, 1888. Serial No. 294,285. (No niodelo T0 a'ZZ whom it may concern.-

a citizen of the United States, residing at Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements in (onunutatm's for Dynamo-Electric Machines, of which the following is a full, clear, and exact description.

In dynamo-electric machines of the trramme type and similar devices a commutator with many faces has to be employed.

are generally formed by the use of strips of t Such faces f tater-leaves.

insulatingdisks d d are slipped over the shaft Be it known that I, EDWARD R. KNowLEs,

B into their proper positions, the commutator leaves F F are introduced, suitably insulated from one another, and fitted in place, the insulated flanges or projections of the disks entering the recesses in the commu- Sy screwing up the nut l) the flanges or projections of the disks are forced i into the recesses in the comnmtator-leaves, l and all the parts are Jirmly bound together,

mature, to which the commutator is fastened i in any suitable manner.

B represents a hollow shell with a fixed flange, C, at one end and a movable flange or nut, D, at the other end, that screws in and out upon it.

E E designate two disks or collars, having annular projections or flanges which face each other when the disks are in position, so as to hold the connnutator-leaves F F and enter into recesses on the ends of the same. As usually constructed, these disks or collars E E are made of insulating material; but this has in practice been found extremely dangerous, because of the liability of the flanges to crack or burn off when the machine is in operation, thus releasing the leaves of the connnutator, which would in such case be thrown with great force in different directions. To obviate this I make the disks or collars E E of metal, with flanges of the same material, and combine them with thin disks (Z d, of similar construction, composed of some suitable insulating material-such, for instance, as canvas impregnated or coated with shellac. These disks or collars E E and their the conunutatrilr-leavcs thus forming a nearlycontinuous cylindrical surface.

It has been found in practice that the surface of such comnultators originally cylindrical becomes worn into ridges and hollows by the brushes. To avoid this difficulty I form two grooves around the periphery of the commutator, as shown at a o. The surface between (t and rt is preferably equal to that between a and (I. The two brushes 1: c, that bear upon the opposite sides of the commu tator, are made as nearly as possible of the exact width of the spaces between the points a and a and o and 1. One brush presses on one section between a and a, the second brush on the other section between a and b. The end motion of the commutator in its revolutions is enough tocause the brushes to come in contact with the entire length of each section of the connnutator, so that they are evenly worn, and no ridges are formed.

By having a brush-holder so constructed that it may hold two brushes side by side in the one rigid holder it is possible to change the brushes in the dynamo without stopping the running of the machineas, for instance, one may be put in between. a and I) while one is running between a and a, and also the same between a and a while one is running between 0' and b, and the ones between a and o and a and Z) withd rawn, and vice versa.

\Vhat I claim as my invention, and desire to secure by Letters Patent is 1. The combination, substantially as shown and described, of the shaft A, the leaves provided with circumferential grooves dividing the surface of the commutator into brushsegments, and the sleeve B, head C, nut D.

and insulating-disks for securing suchleaves to and insulating them from the shaft, as set fortlr 2. In a commutator, the leaves provided with circumferential grooves dividing the surface of the commutator into brush-segments, substantially as described.

3. In a commutator of the general construction described, the grooves a a in and around the face, as shown, for the purposes specified. 10

I11 testimony whereof I have hereunto set my hand this 17th day of July, A. I). 1885.

EDlVARD R. KNOWLES.

Witnesses:

E. JrRENING, ARTHUR C. WEBB. 

